(1) Field of the Invention
The present invention relates to a danger presentation device which generates data for presenting a possible danger caused by a robot which operates in accordance with a motion planning.
(2) Description of the Related Art
Conventionally, robots have been used in production sites and the like. When a robot is used, a worker may come into contact with the robot and get injured. Thus, a safety measure may be taken by surrounding the robot with a safety fence. However, it may be difficult for a worker do some work when a safety fence is installed between the robot and the worker. In this case, for example, it is difficult for the worker and the robot to carry a table by holding both ends of the table, respectively, in a cooperative manner. In the above case, it is also difficult for the robot to hand over a part, a tool, or the like to a worker who does assembly work.
In such a work situation, it is not practical to install a safety fence between a worker and a robot that works cooperatively with the worker, or a robot that works near the worker. Thus, when such a robot is used, a user of the robot needs to pay more attention to safety than is normally needed.
Japanese Unexamined Patent Application Publication No. 2009-123045 discloses a movable robot which visually displays a dangerous area around the movable robot. The dangerous area around the movable robot described in Japanese Unexamined Patent Application Publication No. 2009-123045 varies every moment depending on the direction and the speed of the movement of the robot. The movable robot then determines a dangerous area based on a motion planning such as the movement speed of the robot.
FIG. 38 is a diagram illustrating a dangerous area when the movable robot is stopped. A movable robot 9001 illustrated in FIG. 38 includes a front-side projector 9101, a rear-side projector 9102, a right-side projector 9103, and a left-side projector 9104. A dangerous area 9060 illustrated in FIG. 38 is the dangerous area when the movable robot 9001 is stopped. The dangerous area 9060 is projected to the four projectors 9101, 9102, 9103, and 9104, and is presented to a worker.
FIG. 39 is a diagram illustrating the dangerous area 9060 when the movable robot 9001 illustrated in FIG. 38 is in motion. The dangerous area 9060 illustrated in FIG. 39 is the dangerous area when the movable robot 9001 moves to the left side at a speed V1. The dangerous area 9060 has a left side area of the movable robot 9001 in the moving direction, which is larger than the left side area of the movable robot 9001 when stopped.
FIG. 40 is a diagram illustrating the dangerous area 9060 when the movable robot 9001 illustrated in FIG. 38 moves faster than the speed V1. The dangerous area 9060 becomes even greater than the dangerous area when moving at the speed V1.
FIG. 41 is a diagram illustrating the dangerous area 9060 when the movable robot 9001 illustrated in FIG. 38 operates a left arm 9012. The dangerous area 9060 has an expanded area near the left arm 9012.
However, even when a robot presents a dangerous area around itself, the dangerous area may not be appropriately recognized by a worker. For example, when a robot presents a dangerous area at a place which cannot be viewed by a worker, the dangerous area cannot be appropriately recognized by the worker. Thus the robot and the worker may collide with each other, thereby preventing smooth operation of the robot.
In addition, it is difficult for the worker to precisely recognize a dangerous situation with the dangerous area shown around the robot. For example, it is difficult for the worker to recognize a danger related situation such as in which direction movement would avoid the dangerous situation, in which direction movement would be more dangerous, which area is less dangerous, or how dangerous the current state is. Hereinafter, specific examples are described.
FIG. 42 is a diagram illustrating a problem in a conventional technology. A worker 9061 in the dangerous area 9060 cannot directly view either of a right arm 9011 and a left arm 9012 of the movable robot 9001 from the position of the worker 9061 illustrated in FIG. 42. Thus, even though the worker 9061 recognizes that he is in the dangerous area 9060, he cannot tell which one of the right arm 9011 and the left arm 9012 is moving toward him. Therefore, the worker 9061 cannot tell in which direction an arm of the movable robot 9001 is moving toward him, thus the worker 9061 cannot determine in which direction he should move to avoid the dangerous situation.